Adaptive sample-by-sample controller for under-determined systems

Abstract

A device and method to adapt a model in a underdetermined adaptive system that provides an output in response to an input. A controller provides parameters to the model in a transceiver system, composed of linearizers, equalizers, or estimators as a function of an error signal. The controller and the model parameters are manipulated to allow agnosticism with respect to input signals or model complexity, enabling robust operation and efficient implementation.

The invention claimed is: 
     
       1. A device for adapting a model in an adaptive system that provides a nonlinear radio transmitter output in response to an input with bandwidth variations, the device comprising:
 a controller that provides model parameters to the model in the adaptive system as a function of an error signal; and 
 a parameter control coupled to the controller that controls which set of parameters from multiple sets of parameters, is provided to the model by the controller as a function of bandwidth of the input signal. 
 
     
     
       2. The device of  claim 1  wherein the parameter control counters parameter drift. 
     
     
       3. The device of  claim 2  wherein the parameter control manipulates individual filter parameters. 
     
     
       4. The device of  claim 3  wherein the parameter control counters drift or introduces virtual noise across a system bandwidth to counter parameter drift. 
     
     
       5. The device of  claim 2  wherein the parameter control constrains a set of filter parameters across a dimension of a given time offset or dynamic range level. 
     
     
       6. The device of  claim 5  wherein the parameter control applies a macro constraint to a group of parameters. 
     
     
       7. The device of  claim 6  wherein the group of parameters corresponds to an instance of a dimension and a solution space is restricted. 
     
     
       8. The device of  claim 6  wherein the parameter control maintains a fixed root mean square value of a single or multiple taps of a Volterra series filter/linearizer over time, over dynamic range or over time and dynamic range. 
     
     
       9. The device of  claim 1  and further comprising:
 an analog receiver to receive transmitted signals and provide a feedback signal; and 
 one or more preconditioners coupled to the controller that decorrelates one or more of the error signal, input and feedback signal. 
 
     
     
       10. The device of  claim 9  wherein the preconditioners include at least one of a fixed whitening filter, an adaptive prediction filter, or a self whitening system. 
     
     
       11. A method comprising:
 providing model parameters to a model in an adaptive system for a nonlinear radio transmitter as a function of an error signal; 
 controlling parameters provided to the model to counter parameter drift as a function of a dynamic bandwidth range of an input signal; and 
 transmitting an output radio signal. 
 
     
     
       12. The method of  claim 11  and further comprising decorrelating one or more of the error signal and input signal. 
     
     
       13. The method of  claim 12  wherein decorrelating includes providing at least one of a fixed whitening filter, an adaptive prediction filter, or a self whitening system. 
     
     
       14. The method of  claim 11  wherein controlling the model parameters comprises evolving the model parameters using a sample-by-sample adaptation.